[Mike Kravetz <mkravetz@se...>]

On Fri, Nov 17, 2000 at 01:59:52PM -0800, Rajagopal Ananthanarayanan wrote:
<stuff deleted>
> Are there any thoughts about making the behavior of the
> scheduler configurable? 

Nope,  we have been busy just trying to get multiple runqueues right.

>                         For example, getting the real-time
> scheduler to work correctly can be tricky with multiple run-queues,
> since there is no single ordering entity.

Our approach to solving this problem is to have a dedicated realtime
runqueue where all realtime tasks reside.  This takes care of the
ordering issues.  The thought is that any CPU would be able to schedule
tasks from the realtime runqueue.  As you noted, this can be tricky.

>                                           Relaxing the real-time
> scheduler to say that "thread with highest priority will be
> dispatched in < 1 millisecond" gives some leeway in designing
> distributed queues & their balancing. For harder real-time requirements
> this may be substituted with more stringent balancing algorithms,
> at the cost of basic scheduling complexity.
> 
> Along similar lines there is some work at HP towards a plug-in
> scheduler. You might want to checkout:
> 
> http://resourcemanagement.unixsolutions.hp.com/WaRM/schedpolicy.html

Thanks for the pointer.

-- 
Mike Kravetz                                 mkravetz@...
IBM Linux Technology Center
15450 SW Koll Parkway
Beaverton, OR 97006-6063                     (503)578-3494